National Park Quiz 65: Dunes

Is this observation deck at Sleeping Bear Dunes National Lakeshore perched on a perched dune? Bob Janiskee photo.

1. True or false? Indiana Dunes National Lakeshore is the largest of the three National Park System units that have “Dunes” as part of their name.

2. True of false? The National Park Service has placed a system wide ban on sandboarding, a sport practiced on sand dunes using equipment and techniques similar to surfboarding.

3. True or false? At Great Sand Dunes National Park and Preserve, the Park Service lends special fat tire wheelchairs to visitors who need them.

4. True of false? Canaveral National Seashore protects the longest stretch of undeveloped coastal barrier beaches and dunes along the east coast of Florida.

5. If you knew where to dig into the dunes at ______ , you’d find a goodly number of junk automobiles that were intentionally put there.
a. Point Reyes National Seashore
b. Gulf Islands National Seashore
c. Cape Hatteras National Seashore
d. Sleeping Bear Dunes National Lakeshore

7. Topping out at 123 feet,measured from base to summit, Mount Baldy is the tallest dune at
a. Indiana Dunes National Lakeshore
b. White Sands National Monument
c. Great Sand Dunes National Park and Preserve
d. Mojave National Preserve

8. Which of the following is a type of vegetation that colonizes sand dunes along a shoreline, holding the sand in place and eventually making it possible for shrubs and trees to begin growing there?
a. ryegrass
b. sawgrass
c. pampas grass
d. marram grass

9. The dune scarps seen on coastal barrier islands such as those of Padre Island National Seashore are usually produced by
a. windblown sand
b. storm-driven waves
c. vehicles driven on the beach
d. beach renourishment projects

10. All of the following have singing sand dunes (aka singing sands) EXCEPT:
a. Mojave National Preserve
b. Death Valley National Park
c. White Sands National Monument
d. Great Sand Dunes National Park and Preserve

Extra Credit Question:

11. How can you tell the prevailing wind direction by looking at a barchan dune?

Super Bonus Question:

12. Explain why a visitor who walks on a dune at White Sands National Monument can expect to sink into the surface no more than a couple of inches.

(2) False. Sandboarding is regulated on a park-by-park basis. The general policy seems to be that this form of recreation is to be allowed on park dunes unless and until it is proven to significantly degrade park resources. Great Sand Dunes National Park and Death Valley National Park are two National Park System units that allow sandboarding.

(3) True. The visitor center at Great Sand Dunes has two wheelchairs equipped with special balloon-type tires. One is adult-sized and other is for children. (The adult chair is unsuitable for use by “very large” people.) Both wheelchairs require a helper to push them.

(4) True. The undeveloped beach and dune system at Canaveral National Seashore is approximately 24 miles long.

(6) a -- Most dunes at Sleeping Bear Dunes National Lakeshore were formed atop moraines or drumlins deposited by glaciers. Dunes sitting on top of (or “perched atop”) pre-existing landforms are classified as perched dunes.

(7) a – Mount Baldy is the highest dune at Indiana Dunes National Lakeshore.

(8) d – Several species of grass going by the common names marram grass, beachgrass, and bent grass, are able to colonize coastal sand dunes because they have creeping underground stems (rhizomes) that allow them to grow where shifting sands and high winds create conditions too inhospitable for other plants.

(9) b – On barrier islands, storm-driven waves erode the base of frontal dunes, creating a steep face (scarp) that can be many feet high in some cases. Dune scarps are typically “repaired” by wind and wave action.

(10) c – White Sands National Monument does not have singing sand dunes. Death Valley National Park (Eureka Dunes), Mojave National Preserve (Kelso Dunes), and Great Sand Dunes National Park and Preserve are three of the many locations around the National Park System and the world that have singing sand dunes. The sounds, variously described as roaring, booming, rumbling, squeaking, etc., are produced up to several minutes at a time as winds pass over dunes with dry sand of the right shape, size, and composition. The sand must contain silica. That rules out White Sands, since the dunes there consist of gypsum sand.

(11) Barchan dunes are small, crescent-shaped dunes whose ends always point to the lee of the prevailing wind. That is, the ends point in the downwind direction.

(12) The dunes at White Sands National Monument are composed of pure gypsum (hydrous calcium sulfate). It is easy to walk on the surface of these dunes because only the top few inches are loose sand. The material below this thin layer of loose sand is quite compact because the rainwater that percolates through the surface layer contains dissolved gypsum that glues sand particles together, creating a material similar to plaster of Paris.

Comments

Submitted by Kevin M (not verified) on July 29, 2009 - 5:35am.

Loved this quiz. One of the few I have done well on. Also love the picture at the top of the deck at the dune climb at Sleeping Bear. Last time there, we did that the same day as the 4 miles (round trip) through loose sand to Lake Michigan. Either the beach walk or the dune climb (400 - 500 feet drop at appx 45 degree angle) is a good workout; both the same day is very tough.

Bob, more than once I have had that pleasure. It is like being stung by 3 or 4 bees a second until running for cover.
Last time we went to SB, we took the Sleeping Bear Point trail for the first time. It was great, with beach, forest, dunes, lake views and the ghost forest. For a short trail, it had great variety and quickly became a "must do" for our next visit.

I had a friend up from Florida to visit and we went to Sleeping Bear on a day the wind was whipping up the dunes. My buddy knelt down, face into the wind and started doing some kind of Zen meditation. Sat there for about half an hour while everyone else was sheltering any exposed skin. He said it was an amazing experience. I found it interesting for about one second, exfoliating for about 10 seconds, and painful the rest of the time. I guess I'm not in touch with the spiritual side of sandblasting.

Thanks for the feedback, Mike. There are many NPS units with singing sand, and I regret that space didn't permit listing all of them in that quiz item. Somewhere in my "to-do queue" I've got an outline for an article on singing sand. When I get around to writing it, I'll be sure to mention Apostle Islands National Lakeshore.